How to Change the Coolant in a 2018 GAS GAS TXT GP 125
Maintaining your 2018 GAS GAS TXT GP 125 means keeping the engine cool and protected, especially if you push your bike to the limit on trials courses and technical terrain. The TXT GP 125 features a liquid-cooled, two-stroke engine – changing the coolant regularly is essential for performance, durability, and rider safety. Below you'll find the expert MotoSport guide for changing the coolant on this unique model, along with proprietary tips specific to your bike.
Preparation: What You Need
- Ceramic or light alloy engine-compatible coolant rated to at least –30°C
- Clean drain pan
- Socket wrench set
- Funnel
- Rags or shop towels
- Protective gloves
Step 1: Cool Down & Access the Cooling System
- Never attempt to change the coolant while the engine is hot — wait until the system has cooled completely to avoid severe burns and pressure spray of coolant– Owner's Manual, p.23.
- Remove the seat and then the fuel tank. On the TXT GP, undo the front and top tank securing screws, lift the front, and slide the tank out for easier access– Owner's Manual, p.22.
Step 2: Drain the Old Coolant
- Locate the radiator drain bolt (usually situated at the base or lower coolant hose of the radiator).
- Place a drain pan beneath the drain area.
- Unscrew the drain bolt and let all coolant flow into the pan. Open the radiator cap to speed drainage.
- Dispose of old coolant properly — never pour it down drains or onto the ground.
Step 3: Flush (Optional for Full Service)
- If the coolant was notably dirty, flush the radiator and system with distilled water. Run through the system and drain fully. Repeat until clear.
Step 4: Inspect Hoses & Seals
- Inspect coolant hoses and connections for cracks or wear. TXT GP 125s require tight seals for reliable cooling on long trial rides.
- Replace any suspect hoses with OEM spec parts for maximum longevity.
Step 5: Fill with Fresh Coolant
- Close the drain bolt firmly but do not over-tighten (use manufacturer torque specs if available).
- Slowly pour recommended coolant into the radiator using a funnel, filling to the base of the filler neck.
Step 6: Bleed the System — Air Removal
- With the radiator cap off, start the engine and let it idle to circulate coolant.
- Gently rev the engine a few times to help purge trapped air. Watch for bubbles or drops in level.
- Replace radiator cap once air stops venting. Let the engine reach full operating temperature (but not overheat).
Step 7: Check & Top Off
- Let the bike cool to ambient temperature. Check coolant level again and top off if needed (coolant contracts as it cools).
- After first ride, check the reservoir and radiator levels again. If it repeatedly drops, inspect the system for hidden leaks or air pockets.
TXT GP 125 Model-Specific Notes
- Due to the lightweight frame and high-revving 125cc engine, overheating can quickly impact performance on this model. Always use coolant formulated for aluminum radiators and cases.
- During prolonged, technical rides (slow rock sections), consider checking coolant more frequently — the system is compact and can boil over if neglected.
- TXT GP models are highly sensitive to correct coolant levels; loss of fluid may lead to rapid overheating or engine damage.
Pro Tips for TXT GP Owners
- Never mix different coolants in the system. Drain completely if switching fluid types.
- Regularly inspect your radiator cap seal — a bad seal leads to pressure loss and boiling over.
- Keep vent hoses kink-free for proper airflow and system pressure.
By following these MotoSport steps, you'll keep your 2018 GAS GAS TXT GP 125 running cool and reliable on every section – from club trials to national events. For OEM parts and upgrades, always rely on MotoSport to support your ride.
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Disclaimer: This guide is provided for general informational purposes only and is not intended to replace your motorcycle's official owner's manual. Always refer to your manufacturer's documentation for model-specific instructions, torque specifications, safety procedures, and maintenance requirements. If you are unsure or inexperienced, consider seeking assistance from a qualified mechanic or technician.